All air pumps work pretty much the same - they have a small pump that sucks in the air that is around the pump, and pushes it into the aquarium (or tubing). The only difference is that there is a battery instead of the actually pump being plugged in, which can be idle if the power goes out or there isn’t any extra plugs for the air pump to be plugged into.
A battery-operated aquarium air pump is a device that generates airflow for the aquarium. It performs this function by forcing water from the aquarium and through the air tubing. It is primarily used to provide oxygen to the fish when the tank has no other means of delivering oxygen. The device is powered by a battery, either disposable or rechargeable. Because they are battery operated, they can make a great choice for any fish owner looking to move their tank to a new home.